Add PersistenceDelegate to HostCache

net/dns/host_cache_unittest.cc

Index: net/dns/host_cache_unittest.cc
diff --git a/net/dns/host_cache_unittest.cc b/net/dns/host_cache_unittest.cc
index 15a43e3c5cda78c79898dfe94b585baad1a07a0e..66c0faae5e3b1a3f2a9291e94bcd5b401b0ccc14 100644
--- a/net/dns/host_cache_unittest.cc
+++ b/net/dns/host_cache_unittest.cc
@@ -5,6 +5,7 @@
 #include "net/dns/host_cache.h"
 
 #include <string>
+#include <utility>
 
 #include "base/bind.h"
 #include "base/callback.h"
@@ -31,6 +32,16 @@ bool FoobarIndexIsOdd(const std::string& foobarx_com) {
   return (foobarx_com[6] - '0') % 2 == 1;
 }
 
+class MockPersistenceDelegate : public HostCache::PersistenceDelegate {
+ public:
+  void ScheduleWrite() override { ++num_changes_; }
+
+  int num_changes() const { return num_changes_; }
+
+ private:
+  int num_changes_ = 0;
+};
+
 }  // namespace
 
 TEST(HostCacheTest, Basic) {
@@ -274,7 +285,7 @@ TEST(HostCacheTest, NoCache) {
   HostCache::Entry entry = HostCache::Entry(OK, AddressList());
 
   // Lookup and Set should have no effect.
-  EXPECT_FALSE(cache.Lookup(Key("foobar.com"),now));
+  EXPECT_FALSE(cache.Lookup(Key("foobar.com"), now));
   cache.Set(Key("foobar.com"), entry, now, kTTL);
   EXPECT_FALSE(cache.Lookup(Key("foobar.com"), now));
 
@@ -752,4 +763,77 @@ TEST(HostCacheTest, SerializeAndDeserialize) {
   EXPECT_EQ(address_ipv4, result4->addresses().front().address());
 }
 
+TEST(HostCacheTest, PersistenceDelegate) {
+  const base::TimeDelta kTTL = base::TimeDelta::FromSeconds(10);
+  HostCache cache(kMaxCacheEntries);
+  MockPersistenceDelegate delegate;
+  cache.set_persistence_delegate(&delegate);
+
+  HostCache::Key key1 = Key("foobar.com");
+  HostCache::Key key2 = Key("foobar2.com");
+
+  IPAddress address_ipv4(1, 2, 3, 4);
+  IPAddress address_ipv6(0x20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
+  IPEndPoint endpoint_ipv4(address_ipv4, 0);
+  IPEndPoint endpoint_ipv6(address_ipv6, 0);
+
+  HostCache::Entry entry1 = HostCache::Entry(OK, AddressList(endpoint_ipv4));
+  AddressList addresses2 = AddressList(endpoint_ipv6);
+  addresses2.push_back(endpoint_ipv4);
+  HostCache::Entry entry2 = HostCache::Entry(OK, addresses2);
+  HostCache::Entry entry3 =
+      HostCache::Entry(ERR_NAME_NOT_RESOLVED, AddressList());
+  HostCache::Entry entry4 = HostCache::Entry(OK, AddressList());
+
+  // Start at t=0.
+  base::TimeTicks now;
+  EXPECT_EQ(0u, cache.size());
+
+  // Add two entries at t=0.
+  EXPECT_FALSE(cache.Lookup(key1, now));
+  cache.Set(key1, entry1, now, kTTL);
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  EXPECT_EQ(1u, cache.size());
+  EXPECT_EQ(1, delegate.num_changes());
+
+  EXPECT_FALSE(cache.Lookup(key2, now));
+  cache.Set(key2, entry3, now, kTTL);
+  EXPECT_TRUE(cache.Lookup(key2, now));
+  EXPECT_EQ(2u, cache.size());
+  EXPECT_EQ(2, delegate.num_changes());
+
+  // Advance to t=5.
+  now += base::TimeDelta::FromSeconds(5);
+
+  // Changes that shouldn't trigger a write:
+  // Add an entry for "foobar.com" with different expiration time.
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  cache.Set(key1, entry1, now, kTTL);
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  EXPECT_EQ(2u, cache.size());
+  EXPECT_EQ(2, delegate.num_changes());
+
+  // Add an entry for "foobar.com" with different TTL.
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  cache.Set(key1, entry1, now, kTTL - base::TimeDelta::FromSeconds(5));
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  EXPECT_EQ(2u, cache.size());
+  EXPECT_EQ(2, delegate.num_changes());
+
+  // Changes that should trigger a write:
+  // Add an entry for "foobar.com" with different address list.
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  cache.Set(key1, entry2, now, kTTL);
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  EXPECT_EQ(2u, cache.size());
+  EXPECT_EQ(3, delegate.num_changes());
+
+  // Add an entry for "foobar2.com" with different error.
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  cache.Set(key2, entry4, now, kTTL);
+  EXPECT_TRUE(cache.Lookup(key1, now));
+  EXPECT_EQ(2u, cache.size());
+  EXPECT_EQ(4, delegate.num_changes());
+}
+
 }  // namespace net